1. Field of the Invention
The present invention relates generally to a parking brake system, and more particularly, to a parking brake system, which easily controls the stroke of a parking lever.
2. Description of the Prior Art
Referring to FIG. 1, a conventional parking brake system is designed to operate a brake device (not shown) mounted to the rear wheels (not shown) of a car, by operation of a cable 3 strained in a direction as shown by the arrow 4 of the drawing, when a parking lever 1 is pulled upward as shown by the arrow 2 of the drawing. Once the brake is applied, a ratchet unit 5 prevents unexpected release of the brake device, thus maintaining the car in a braked state.
The operation of the ratchet unit 5 is as follows. When the parking lever 1 is pulled in the direction as shown by the arrow 2 of FIG. 1, a brake pawl 7 moves in a direction as shown by the arrow 12 of the drawing toward a ratchet 11 integrated with a brake plate 9. Thereafter, the brake pawl 7 engages the ratchet 11 at a predetermined position, so an unexpected release of the brake device is prevented as far as there is no additional force applied to the brake device, thus maintaining the car in the braked state.
Such a conventional parking brake system is designed to reduce the stroke of the parking lever 1, by loosening a nut (not shown) of a cable adjusting part 13 and then retightening the nut while straining the cable 3, when the stroke of the parking lever 1 is undesirably excessive. In this case, the extendable range of the cable 3 is restricted within the length of the cable adjusting part 13. Therefore, the lining clearance of the rear wheels must be additionally adjusted to control the stroke of the parking lever 1, when full extension of the cable 3 within the length of the cable adjusting part 13 fails to sufficiently control the stroke of the parking lever 1. However, even when the lining clearance of the rear wheels is adjusted in this way, the stroke of the parking lever 1 may be still excessive. In such a case, there is no solution to cope with the undesirably excessive stroke of the parking lever 1. Therefore, the conventional parking brake system has a problem in that cars may roll when parked on sloped street, with an inevitable excessive stroke of the parking lever 1.
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and provides a parking brake system, which reliably controls the stroke of a parking lever.
The present invention provides a parking brake system, comprising a ratchet bracket having a ratchet and rotatably hinged to a brake plate, a first slot formed on the ratchet bracket, a second slot formed on a cam provided on a lower portion of a parking lever, and a parking lever control unit connecting the first slot to the second slot and being adjustable in a length thereof, with the junction of the parking lever control unit and the second slot rotatably hinged to the brake plate.